Methods and apparatus for in situ generation of power for devices deployed in a tubular

ABSTRACT

A device, system, and methods of power generation in situ in a hydrocarbon well are disclosed. A power generator for deployment in a hydrocarbon well tubular may comprise a housing adapted for deployment within a hydrocarbon well tubular; a mechanical to electrical power converter disposed at least partially within the housing, the mechanical to electrical power converter adapted to create an electric current when physically stressed; and a current converter operatively coupled to the mechanical to electrical power converter. Devices may be deployed downhole and operatively coupled to the power generator for their electrical power. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope of meaning of the claims.

FIELD OF THE INVENTION

The inventions are related to generation of electrical power within a tubular. More specifically, the inventions are related to generation of electrical power within a hydrocarbon well tubular for use with electrically power devices also deployed in the hydrocarbon well.

BACKGROUND OF THE INVENTION

For decades, operators have opened and closed valves across producing zones and used electrical cables for communications and power delivery for gauges deployed in the well. The idea was generally to allow a primary zone to produce to the end of its life and then to open a second zone for access to additional reserves. Traditionally, these valves were opened and closed mechanically through wireline. Such interventions, in shallow waters or onshore, are relatively inexpensive operations and usually involve only minimal loss of production time.

As the industry moved farther offshore, the cost of support vessels for such operations and the complexity of re-entering subsea wells soon combined to make the cost of intervention sufficiently high as to scuttle the economics of any but the most significant secondary reserves.

Over time, traditional mechanical actuation was replaced with remotely actuated hydraulics systems. The hydraulic systems deployment complexities have likely contributed to several failures offshore during the past few years, leading many service companies to the conclusion that, while hydraulics have their place, all-electric systems are the future of intelligent completions. Typically, electrical cables have been used to provide power and communications for gauges and flow control devices in the wellbore, raising the completions costs significantly. Cables are also one of the major sources of failures that impact the production of hydrocarbons. These failures created the risk of not being able to control the flow valve and to lose the ability to acquire data from downhole affecting the operator's ability to optimize production.

In addition, the high costs and risks of wellhead design with cable entrance capability as well as downhole hardware deployment with cable feedthrough connectors make the deployment of intelligent completions and gauges uneconomical.

It would therefore be desirable to eliminate surface system power generators and power cables running from the surface to allow smaller intelligent completions systems that can be deployed deeper in wellbores due to no losses through cables and elimination of flyback currents on cables. Such systems may further allow sensors to be deployed in well zones that may have not been accessible using electrical cables, e.g. using wireless communications modules powered by downhole power generators.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, aspects, and advantages of the present invention will become more fully apparent from the following description, appended claims, and accompanying drawings in which:

FIG. 1 is a block diagram of an exemplary embodiment of a power generator;

FIG. 2 is a block diagram of an exemplary embodiment of a power generator;

FIG. 3 is a partial perspective of an exemplary doughnut shaped configuration;

FIG. 4 is a partial perspective of a second exemplary configuration;

FIG. 5 is a partial perspective of an exemplary system in partial cutaway illustrating use of the power generator in a system downhole; and

FIG. 6 is a flowchart of an exemplary method.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Referring now to FIG. 1, downhole power generator 50 may be configured to be actuated downhole and used to generate electricity in well 10 (FIG. 5), e.g. by using stressable material 52 such as piezoelectric or magneto-restrictive stressable material 52. Downhole power generator 50 may provide for direct action between wellbore fluid flow and stressable material 52 to generate electrical energy and may be used to help eliminate inefficiencies related to picking up pressure fluctuations occurring inside the tubing walls.

The main sources of energy in a wellbore include flow, vibration, pressure, and noise. Power generator 50 may be used to provide a non-movable or sealed hardware approach to harness or otherwise use the energy. In a preferred method, force generated by the flow is routed to power generator 50 which converts the mechanical motion of the force into electrical energy.

Power generator 50 may comprise housing 74 which has been adapted for deployment within a hydrocarbon well tubular and in which a mechanical-to-electrical-power converter, e.g. power converter 51, current converter 72, and/or power storage medium 73, are at least partially disposed.

Mechanical to electrical power converter 51 will comprise stressable material 52 that, when stressed, creates an electrical current, e.g. by a stack of piezoelectric, magneto-restrictive material or any other material that would cause vibration near the power generator area. In currently preferred embodiments, stressable material 52 is either piezoelectric or magneto-restrictive material that will be stressed by the flow vibration created in the well. For example, stressable material 52 may be stressed by the vibration of the production tubing in the well, by the force exerted by the flow in the well, or by the generation of acoustic signals at downhole wireless gauges.

Mechanical to electrical power converter 51 will typically convert vibrational stress to alternating current. In experimental environments involving piezoelectric material, the amplitude and frequency of the induced voltage was found to be directly proportional to the mechanical deformation of the piezoelectric material. The electrical charges developed by stressing the piezoelectric material decayed with time because of the internal resistance. Experiments performed in the past have indicated that at a one kilohertz frequency a power output of as much as one hundred watts per cubic centimeter and efficiency of as high as seventy percent has been obtained from piezoelectric material.

Current converter 72 may be used to convert alternative current produced by stressable material 52 into direct current for storage in power storage medium 73, e.g. a capacitor bank or a rechargeable battery pack.

In some embodiments, power generator 50 will include mechanical vibration amplifier 70 that will interface with stressable material 52. Mechanical vibration amplifier 70 may comprise a mechanical vibration amplifier to provide a higher level of vibration to increase the power generation capability of power generator 50. For example, mechanical vibration amplifier 70 may be used to directly or augmentingly compress and release stressable material 52 to generate electricity.

In a currently preferred embodiment, piezoelectric assemblies 52 are mounted on the inside of tubing 10 (FIG. 5) and exposed to hydrostatic pressure in the well. A ceramic coating may be used to coat stressable material 52 to prevent or otherwise inhibit erosion as the hydrocarbons flow by stressable material 52. The ceramic coating application to stressable material 52, e.g. a piezoelectric assembly, may be performed at room temperature which helps eliminate concerns and problems related to applying coatings at extremely high temperatures that could damage stressable material 52.

Referring now to FIG. 2, downhole power generator 50 may be used to provide a direct interaction between the wellbore fluid flow and stressable material 52, e.g. a piezoelectric stack, to generate energy. One or more electronics modules may be required to gather, rectify, and store the energy generated by stressable material 52.

In a preferred embodiment, power conditioner 53 comprises rectifier 53, tank circuit 54, harvester 55 and regulator 56. An inductor may be operatively coupled to mechanical to electrical power converter 51, the inductor adapted to cancel a capacitive part of impedance of the mechanical to electrical power converter 51. This cancellation may minimize the impedance.

Power conditioner 53 may comprise a rectifier or bridge.

Tank circuit 54 may be present to accept the output of power conditioner 53 and act as a voltage regulator, e.g. a voltage doubler. The output of tank circuit 54 may be routed to one or more additional power conditioners. For example, the output of tank circuit 54 may be routed to power harvester 55, which may include a harvesting monitor switch, and then on to voltage regulator 56.

Electrical energy may be stored in storage medium 73 which may include a capacitor bank, a rechargeable battery pack, or the like, or a combination thereof.

Electrical energy, once generated and processed, e.g. by the circuitry illustrated in FIG. 2, may then be made available though numerous pathways, e.g. via wire or coaxial cable to one or more tools such as acoustic tool 60.

Referring now to FIG. 3, downhole power generator 10 may be configured in a doughnut or substantially toroid shape design, e.g. where stressable material 52 is located in pressure balanced apparatus 58 as part of a downhole tool. Hydrocarbon flow can impact pressure bellows 59 coupled to downhole power generator 10 (FIG. 1) causing a force to be exerted onto stressable material 52 due to flow, causing electricity to be created. Note that only a few pressure bellows 59 and that only a few stressable materials 52 are marked in FIG. 3.

Referring now to FIG. 4, downhole power generator 50 may be configured as a device, e.g. tool 58, that can be interfaced to acoustic tool 60 such as an acoustic generator (FIG. 6) that causes pipe 20 to vibrate inside wellbore 10. In this exemplary embodiment, one or more housings 74 containing stressable material 52 may be arranged as part of a tool, e.g. tool 58. The vibration causes stressable material 52 to generate energy which is routed at least partially to power storage medium 73 (FIG. 1).

Referring to FIG. 5, in an exemplary intelligent completion system well 10 with wireless communications module 60 and power generator 50, use of a downhole power generation may eliminate use of an electrical cable and reduce the cost of the completions system. This may be especially true if power generator 50 is deployed downhole cooperatively with wireless communications system 60. Accessibility to such power generation may allow deployment of intelligent completions in areas that were not accessible to cable based systems, e.g. by having in situ power generation and wireless communications.

Casing 20, autolock 21, packer 22, line handler 24, packer 26, and tie back seal stem 28 are all shown as illustrations of typical devices in downhole well 10 and are not meant to limit the present invention in any way. Other such typical devices may be sensors, control modules, or the like, as those terms are used herein, i.e. with respect to placement downhole.

Traditionally, development of completion equipment has been based on the deployment of single devices that perform an individual function inside the wellbore and work independently of any other component of the completion. Consequently, the actuation of hydro-mechanical equipment and the acquisition of downhole parameters from electronics sensors have been difficult and costly. Further, measurement of downhole parameters during the production has typically been performed by tools that are lowered into, and retrieved from, the wellbore via wireline. Other methods of measuring downhole parameters may include installation of pressure and/or temperature tools and flow meters permanently in the production tubing string. These tools are typically placed on the outside of the production tubing and are connected to the surface data acquisition system through cables mounted along the outside of the tubing string. The actuation of downhole devices to control flow is normally performed manually, e.g. using a mechanical device attached to coil tubing or wireline, lowered into the wellbore and used to shift such devices as sliding sleeves or to set a packer.

Further, wireless communications systems and the power generation system of the present inventions may also be used to create wireless-based sensor modules which may be located almost anywhere in wellbore 10. The interface of these systems to intelligent completion systems may be used to allow for complete and independent hydrocarbon flow control and communications in and out of the wellbore in any section of well 10.

In an embodiment, downhole power generator 50 may be coupled with wireless communications system 60 and provide the capability to communicate through the production tubing, e.g. 20, using stress waves to transmit and receive digital data and commands inside wellbore 10. A system using wireless communications systems, e.g. 60, and power generator 50 may be used in applications requiring information related to well status, geological formations, and production status. Wells where multiple zones are being produced, deep gas wells, and multilaterals may benefit from the development of such a system due to the ease of deployment and the elimination of cables that restrict the placement of gauges in the well. A system according to the present inventions may positively impact intelligent well applications, permit an increase in hydrocarbon production, and lead to a decrease in the operating costs by decreasing the number of interventions required in the well.

System 100 may be adapted for downhole control and comprise a control module adapted (not shown in the figures) to be deployed downhole; wireless transceiver 60 operatively in communication with the control module, where wireless transceiver 60 is adapted to be deployed downhole; and power generator 50 operatively coupled to wireless transceiver 60. In certain embodiments, system 100 may be further adapted for use with an intelligent completion system, as that term will be familiar to one of ordinary skill in these arts.

The control module may further comprise a sensor, a gauge, a meter, a flow control device, or the like, or a combination thereof. For example, system 100 may be adapted for deployment at a subsea level at a hydrocarbon transmission pipeline to provide information related to the flow of hydrocarbon through the pipeline, the information comprising pressure, temperature, flow, or the like, or a combination.

Transceiver 60 may comprise an active transceiver, a repeater, or the like, or a combination thereof.

Power generator 50 comprises stressable material 52 adapted to create an electric current when physically stressed. Power generator 50 may be a separate power station deployed as part of the production tubing, e.g. 20, and may be adapted to be used to generate and store power to be transferred to mobile system temporarily attached to power generator 50. Power generator 50 may be deployed through tubing 20 for use with permanent or with systems that perform a temporary service in wellbore 10.

Fluid flowing in a downhole pipe may create vibrations, e.g. in pipe 20 used downhole, where the vibrations are usable by stressable material 52 to allow generation of electricity by stressable material 52. The electricity generated may then be used to provide power for a sensor (not shown in the figures) operatively in communication with power generator 50, e.g. disposed within or otherwise connected to power generator 50.

Systems 100 may be disposed proximate a subsea wellhead and control assembly may generate electricity as hydrocarbons flow from downhole to a surface location. Electrical power generated by power generator 50 may provide at least partial power for electronics and electro-mechanical devices located proximate the subsea wellhead.

In the operation of exemplary embodiments, referring now to FIG. 6, in a preferred embodiment, power generation may be achieved by stressing stressable material 52 (FIG. 1) such as piezoelectric or magneto-restrictive material, where the stress arises, at least on part, from production flow vibration induced in production tubing 20 (FIG. 5). A mechanical vibration amplifier, e.g. 70 (FIG. 1) may be used to increase the power generated by stressable material 52. A battery pack and/or capacitor bank, e.g. 73 (FIG. 1) may be used to store the energy generated by stressable material 52. The amplitude and frequency of the induced voltage is typically directly proportional to the mechanical deformation of stressable material 52. The electrical charges developed by stressing stressable material 52 will typically decay with time because of the internal resistance so that DC power cannot be generated. An AC to DC converter, e.g. 72 (FIG. 1), may be included as part of the power circuit. The power output of stressable material 52 may be optimized by using an inductor to cancel the capacitive part of the impedance minimizing the source impedance. At resonance, the output power is typically limited by the resistive component of stressable material 52.

Electrical power may be generated from within tubular 20 (FIG. 5) by deploying power generator 50 (FIG. 1) within tubular 20 (FIG. 5), where power generator 50 comprises mechanical vibration amplifier 70 (FIG. 1), mechanical to electrical power converter 51 (FIG. 1), power conditioner 72 (FIG. 1), and power storage medium 73 (FIG. 1) (e.g., steps 210-220). Power generator 50 is operatively coupled to a source of vibration, e.g. fluid flows or tubular 20 (e.g., step 230). Electrical current is generated using power generator 50 when exposed to the physical stress (e.g., step 240). An outlet for electricity generated by power generator 50 may be provided to allow access to the electricity generated by power generator 50.

For systems, e.g. the system illustrated in FIG. 5, a device that requires electric power such as acoustic module 60 may be operatively coupled within tubular 20 (FIG. 5) to the outlet of power generator 50. Acoustic generator 60 may itself be adapted to vibrate tubular 20.

A system comprising a downhole tool, e.g. as illustrated in FIG. 5, may be implemented by deploying a control module (not shown in the figures) downhole (step 200). In an embodiment, a device such as wireless transceiver 60 (FIG. 5) may be deployed downhole, either before or after deployment of the control module where wireless transceiver 60 is operatively in communication with the control module (step 210). Power generator 50 (FIG. 5) may be deployed downhole where power generator 50 is operatively coupled to wireless transceiver 60, e.g. using wires or cables (step 220). As described above, power generator 50 comprises stressable material 52 (FIG. 1) adapted to create an electric current when physically stressed. Power generator 50 is exposed to a source of physical stress downhole, e.g. production fluid flow or vibration (step 230). Power generator 50 generates electrical current when exposed to the physical stress and the power generated is used by the device, e.g. wireless transceiver 60.

A portion of the electricity generated by power system 50 may be stored in power storage system 73 deployed downhole, e.g. power generator 50 may comprise power storage system 73.

It will be understood that various changes in the details, materials, and arrangements of the parts which have been described and illustrated above in order to explain the nature of this invention may be made by those skilled in the art without departing from the principle and scope of the invention as recited in the following claims. 

1. A power generator for deployment in a hydrocarbon well tubular, comprising: a. a housing adapted for deployment within a hydrocarbon well tubular; and b. a mechanical to electrical power converter disposed at least partially within the housing, the mechanical to electrical power converter adapted to create an electric current when physically stressed by a force present within the hydrocarbon well tubular
 2. The power generator of claim 1, wherein the mechanical to electrical power converter comprises stressable material, further comprising at least one of (i) a piezoelectric material or (ii) a magneto-restrictive material.
 3. The power generator of claim 1, further comprising a current converter operatively coupled to the mechanical to electrical power converter.
 4. The power generator of claim 3, wherein the current converter comprises at least one of (i) an alternating current to direct current converter or (ii) a direct current to alternating current converter.
 5. The power generator of claim 1, further comprising a mechanical vibration amplifier operatively coupled to the mechanical to electrical power converter and adapted to increase power generated by the mechanical to electrical power converter.
 6. The power generator of claim 1, further comprising a power storage medium.
 7. The power generator of claim 6, wherein the power storage medium comprises at least one of (i) a battery pack or (ii) a capacitor bank.
 8. The power generator of claim 1, further comprising an inductor operatively coupled to the mechanical to electrical power converter, the inductor adapted to cancel a capacitive part of impedance of the mechanical to electrical power converter.
 9. The power generator of claim 8, wherein the cancellation minimizes the impedance.
 10. A power generator, comprising: a. a mechanical vibration amplifier; b. a mechanical to electrical power converter operatively coupled to the mechanical vibration amplifier and adapted to create an electrical current when vibrated; c. a power conditioner operatively coupled to the power converter; and d. a power storage medium operatively coupled to the power converter.
 11. The power generator of claim 10, further comprising a coating adapted to retard erosion of a predetermined portion the power module.
 12. The power generator of claim 11, wherein: a. the coating comprises a ceramic; and b. the predetermined portion of the power module comprises the mechanical to electrical power converter.
 13. The power generator of claim 10, wherein the mechanical to electrical power converter is adapted to be deployed at least partially within the tubular and to be exposed to hydrocarbon flow within the tubular.
 14. The power generator of claim 10, wherein: a. the power module comprises a doughnut shaped design; and b. the mechanical to electrical power converter is disposed in a pressure balanced apparatus as part of a downhole tool.
 15. The power generator of claim 14, further comprising a pressure bellows operatively coupled to the mechanical to electrical power converter and adapted to cause a force to be exerted onto the mechanical to electrical power converter in the presence of fluid flowing in the tubular.
 16. The power generator of claim 10, wherein: a. the power module comprises a plurality of housings; and b. the mechanical to electrical power converter comprises a plurality of the mechanical to electrical power converter, each housing at least partially containing one of the plurality of mechanical to electrical power converters.
 17. A method of generating power from within a tubular, comprising: a. deploying a power generator within a tubular, the power generator comprising a mechanical vibration amplifier, a mechanical to electrical power converter, a power conditioner, and a power storage medium; b. operatively coupling the power generator to a source of vibration; and c. providing an outlet for electricity generated by the power generator.
 18. The method of claim 17, further comprising operatively coupling a device within the tubular that requires electric power to the outlet of the power generator.
 19. The method of claim 18, wherein the device is an acoustic generator adapted to vibrate the tubular.
 20. A system for downhole control, comprising: a. a control module adapted to be deployed downhole; b. a wireless transceiver operatively in communication with the control module, the wireless transceiver adapted to be deployed downhole; and c. a power generator operatively coupled to the wireless transceiver, the power generator comprising a stressable material adapted to create an electric current when physically stressed.
 21. The system of claim 20, wherein the system is adapted for use with an intelligent completion system.
 22. The system of claim 21, wherein the control module comprises at least one of (i) a sensor, (ii) a gauge, (iii) a meter, or (iv) a flow control device.
 23. The system of claim 20, wherein the transceiver comprises at least one if (i) an active transceiver or (ii) a repeater.
 24. The system of claim 20, wherein the power generator is adapted for use as a separate power station to be deployed as part of a production tubing and is further adapted to be used to generate and store power to be transferred to a mobile system temporarily attached to the power generator.
 25. The system of claim 20, wherein the power generator is deployed through tubing for use with at least one of (i) a permanent service in the wellbore or (ii) a system that performs a temporary service in the wellbore.
 26. The system of claim 20, wherein the system is adapted for deployment at a subsea level at a hydrocarbon transmission pipeline to provide information related to the flow of hydrocarbon through the pipeline, the information comprising at least one of (i) pressure, (ii) temperature, or (iii) flow.
 27. The system of claim 20, wherein: a. fluid flowing in a downhole pipe creates a vibration usable by the stressable material to allow generation of electricity by the stressable material; and b. the electricity generated is used to power a sensor operatively in communication with the power generator.
 28. The system of claim 20, wherein: a. the system is disposed proximate a subsea wellhead and control assembly to generate electricity as hydrocarbons flow from downhole to a surface location; and b. electrical power generated by the power generator provides at least partial power for electronics and electromechanical devices located proximate the subsea wellhead.
 29. A method of deploying a downhole tool, comprising: a. deploying a control module downhole; b. deploying a wireless transceiver downhole, the wireless transceiver operatively in communication with the control module; c. deploying a power generator downhole, the power generator operatively coupled to the wireless transceiver, the power generator comprising a stressable material adapted to create an electric current when physically stressed; d. exposing the power generator to a source of physical stress downhole; and e. generating electrical current using the power generator when exposed to the physical stress.
 30. The method of claim 29, wherein the physical stress is obtained using vibration generated at least partially by production flow.
 31. The method of claim 29, wherein the power generator comprises at least one of (i) a piezoelectric material or (ii) a magentoresistive material.
 32. The method of claim 29, wherein the power generator comprises a power storage system deployed downhole.
 33. The method of claim 32, further comprising storing a portion of the electricity generated by the power system in the power storage system deployed downhole. 